1. Field of the Invention
The invention concerns a "record/not record" device for a recording cassette, specifically a device for blocking or unblocking an opening in a wall of the cassette to enable mechanism of the recorder to sense the record/not record status of the cassette.
2. Description of the Related Art
Magnetic tape cassette recorders typically incorporate a mechanism that senses whether a "record/not record" opening in a wall of a cassette is blocked or unblocked. When the opening is unblocked, the recording function is disabled, thus preventing accidental erasure. Hideaki European Pat. Publication No. 0,169,546 (filed July 23, 1985 based on a Japanese filing date of July 23, 1984) says that in prior magnetic tape videocassettes, the record/not record opening is either provided with a removable cap or is formed by breaking a partial cut-out along a weakened edge. Hideakai says that the former involves the problem of losing the cap and the latter requires something such as adhesive tape to close the opening in order to make a new recording. As Hideaki also points out, in either case it is difficult to check the recording status of the cassette, because the opening is hidden when the cassette is in position on the recorder.
Hideaki's solution to this problem is to extend the record/not record opening to the label side of the cassette and to position a slidable plug element in the opening. A coil spring biases the plug element upwardly, but the plug element can be forced downwardly and locked by being rotated 90.degree. to close the record/not record opening. When the plug element is in the "not record" position, its upper extremity is flush with the label side of the cassette, and when the plug element is in the "record" position, its upper extremity is recessed from the label side, thus providing a visual indication of the recordability of the cassette.
Hideaki's record/not record mechanism is being used in a digital videocassette being marketed by Sony Corp. under standards promulgated by Society of Motion Picture and Television Engineers. The standards call the record/not record opening "user hole #1" and require its plug element to be seen from the label side of the cassette and to be green in color to contrast visually with the black walls of the cassette. Unfortunately, the green plug element can be seen in both positions and, upon quick inspection, a user might accidentally think that the plug is recessed when it is not, or vice versa. The Sony cassette requires a special tool to switch the plug element between its flush and recessed positions.
In a number of recording cassettes used for other purposes, a slide mounted in a wall of the cassette blocks or unblocks a record/not record opening.